This invention relates to torque transmitting mechanical elements, above all gears adapted to damp or reduce vibration thereof in operation and reduce noise generated therefrom.
It is well known that when such mechanical elements usually made of hard or rigid metal such as iron are respectively rotated to transmit driving power from one to the other they are often vibrated to generate undesired noise particularly when running at high speed.
In order to reduce noise, gears of soft or flexible material such as artificial resin have been proposed and actually used in some field. Such so-called plastic gears, however, are not satisfactory due to that when too highly loaded the gear teeth often slip over which not only makes driving unreliable but also often causes dangerous situation above all when in high speed operation.
In order to damp such vibration or "hammering" and noise, U.S. Pat. No. 3,834,248 discloses a gear adapted to receive oil under pressure via the shaft having the oil conduit formed therein so as to maintain a film of oil on the torque transmitting teeth. This is, however, naturally disadvantageous from the economical view point.
It has been proposed to fix a piece, ring and the like of elastomer on the gears. This is preferable in view point of the cost, but found unsatisfactory in that thickness or volume of such damping material must be considerably large and that when gears are arranged in the box filled with lubricant oil or supplied with much amount of oil applied such material is deteriorated.